1. Field of the Invention
The present invention relates to an occlusion device for treating congenital heart disease, such as patent foramen ovale (PFO), atrial septal defect (ASD), patent ductus arteriosus (PDA) or ventricular septal defect (VSD), etc.
2. Description of the Prior Art
Congenital heart diseases include patent foramen ovale (PFO), atrial septal defect (ASD), patent ductus arteriosus (PDA) and ventricular septal defect (VSD), etc. PFO and ASD are openings in the wall between the right atrium and left atrium of the heart thereby creating the possibility that the blood could pass from the right atrium to the left atrium. But the defect size of PFO is usually smaller than that of ASD and the defect will not extend perpendicularly to the septal wall, i.e. left atrial septal defect is not concentric with that of the right atrium. Once the occluder has been placed, it will prevent the thrombus from entering into the left atrium. Furthermore, the atrial septal defect (ASD) is usually larger and requires repair. Currently there are many types of endocardiac occlusion devices for treating congenital heart diseases. These occluders are delivered to the desired location by a corresponding catheter.
Mechanical occlusion devices for treating congenital heart diseases have been proposed in the past, some of which are disclosed in Franker et al., Chinese patent application No. 97194488.1; Franker et al., Chinese patent application No. 98808876.2; and Michael et al., and Chinese patent application No. 98813470.5. This kind of device includes a support mesh with contractibility and biocompatible materials, and the biocompatible materials are connected to the circumference of the support mesh. The support mesh, which is put into the catheter first, is delivered to the desired location, and then is deployed to close the septal defect. This kind of device is easy to withdraw and has excellent centricity. However, the left disc of this device directly contacts blood, so that it can form thrombus and release harmful metallic elements more easily. Moreover, because the two discs are a whole, they cannot automatically adjust the angle to adapt to the unique anatomy of the patient. Meanwhile, if the left disc is not deployed completely, the operation becomes more complicated. In addition, with the existing technique and the operation method, it is very difficult to determine the size and shape of the septal defect precisely, as well as the limit of the waist size, thereby causing many difficulties to physicians, such as selection error, etc. If an oversized device is selected, the occluder will form a cucurbit shape, and result in an imperfect closing effect.
Accordingly, it would be advantageous to provide a reliable occlusion device which can automatically adjust the angle to adapt to the unique anatomy of the patient.